You would like to know where to find your event domain. You would also like to know where you can customise this.
Navigate to Event Setup > Settings > Event Domain and this feature is included in all plans.
You can also change the subdomain of your event to something like "https://bookfairsummit.heysummit.com" using the example from the screenshot below.
If you want to set up a custom domain, here's a step-by-step guide to walk you through.
Please note that your event dashboard will consistently display the heysummit domain, while the custom domain will be utilized for the public event pages.